The long term goal of this study is to understand anemia caused by malaria infection. Severe malarial anemia (SMA), has its greatest effect on children and pregnant women. The major way to manage malarial anemia is by blood transfusion, which is expensive. In addition, countries impacted by malaria have blood storages with high incidence of HIV and hepatitis, making the need for alternate treatment strategies critical. This work will help give insight into the pathology of this blood disease, with the ultimate goal of developing new medical approaches. The specific hypothesis driving this proposed research is that a protein called rhoptry-associated protein 2 (RAP2) plays a central role in the onset of SMA. RAP2 is currently being investigated as a potential vaccine candidate, but its in vivo role is unknown. Characterization will allow for a better assessment of RAP2 as a vaccine. Since our objective is to determine the in vivo role of RAP2, our studies will be conducted using the malaria model rodent parasite Plasmodium berghei. The specific aims have been designed to characterize the P. berghei orthologue of the P. falciparum RAP2 (PfRAP2) and to investigate its potential role in a living system. Aim 1 will confirm the cellular location of PbRAP2 and determine if it is necessary for in vivo growth and invasion. Localization of PbRAP will be accomplished by the use of indirect immunofluorescence assays. We will also create a PbRAP2 deletion mutant strain (APbRAP2) to determine its role in infection. Aim 2 focuses on investigating the erythrocyte binding capability of PbRAP2 and identifying its potential binding partners. Erythrocyte binding assays will determine if the binding properties reported for PfRAP2 are conserved in PbRAP2. Candidate binding partners on the erythrocyte surface will be identified by pull-down assays. Aim 3 will investigate the role of PbRAP2 in the manifestation of SMA in mice. We will assess the contribution of PbRAP2 in SMA development using a malarial anemia mouse model that will allow us to compare the hematological effects of infections with wild-type and APbRAP strains of P. berghei. Using this same model we will also examine the effects PbRAP2 has on cytokines, which have been implicated in SMA, by comparing the profiles of mice challenged with either the wild-type or APbRAP2 strain. Severe malarial anemia (SMA) is a lethal manifestation of infection that afflicts women and children in many developing countries. The full mechanism of disease associated with SMA is unknown. This study plans to shed light on how rhoptry-associated protein 2 (RAP2) contributes to the presentation of SMA.